The synthesis, structure, conformation, and dynamics of a new rotane family consisting of four-membered rings are described. All syntheses are based on bicyclobutylidene (9): [2+1] cycloaddition of cyclobutylidene yields [3.4]rotane (5) (9−5), [2+2] cycloaddition of trimethyleneketene followed by spiroalkylation of the resulting trispiroketone 10 yields [4.4]rotane (6) (9−10−13−14−6), homologization